PURPOSE: To substantially improve coating capacity by connecting on the downstream side of a cutoff valve to a coating supply passage a suction means for removing by suction the residual coating from the downstream side of the cutoff valve of the coating supply passage with this valve closed.

CONSTITUTION: On the downstream side of a cutoff valve 4, a coating supply passage 2 connects with a suction passage 8 through which the residual coating is removed by suction from the downstream side 2b of the cutoff valve with this valve closed by drawing air from a spray outlet 1a. This suction passage 8 is provided with a second valve 9 for cutting on and off the communication between the downstream side 2b of the passage 2 and the suction passage 8 and with a second venturi pump 10 for imparting a sucking force to the suction passage 8. To remove the residual coating by suction from the downstream side 2b of the passage 2, the secondary venturi pump 10 is driven following the termination of the coating spray and, at the same time, a second valve 9 is opened.